Distribution of intraocular pressure and related risk factors in a highly myopic Chinese population: an observational, cross-sectional study

Clinical relevance: Those with high myopia are more likely to have glaucoma compared to those without myopia and intraocular pressure was a key factor for developing glaucoma. Thus, investigating the distribution of intraocular pressure and associated factors among those with high myopia is of high importance. Background: The aim of this work is to investigate the distribution of intraocular pressure and the correlated risk factors in a highly myopic Chinese population. Methods: A total of 884 Chinese participants with bilateral high myopia (≤ −6.00 D spherical power) were included from the Zhongshan Ophthalmic Center-Brien Holden Vision Institute High Myopia Cohort Study. All participants underwent a comprehensive ocular examination, including ocular biometry, cycloplegic refractometry, and intraocular pressure measurement with Goldmann applanation tonometry. Information on smoking and drinking status was also collected. Results: The mean spherical equivalence of left eyes was −10.02 ± 3.58 D with a mean axial length of 27.48 ± 1.55 mm. The overall mean intraocular pressure was 15.1 ± 2.4 mmHg (95% confidence interval, 15.0 to 15.3 mmHg). The intraocular pressure in the −6.00D to −7.99D spherical equivalence group, −8.00D to −9.99D spherical equivalence group, and ≤ −10.00 D group were 15.3 ± 2.4 mmHg, 15.1 ± 2.5 mmHg, and 15.0 ± 2.4 mmHg, respectively (p = 0.979). In multiple regression models, intraocular pressure in high myopes was not associated with spherical equivalence (p = 0.354) or axial length (p = 0.601), but significantly higher in those who were younger (non-standardised beta, −0.018; p = 0.007), smoked tobacco (non-standardised beta, 1.085; p = 0.001) and had greater central corneal thickness (non-standardised beta, 0.021; p < 0.001). Conclusion: Intraocular pressure was 15.1 ± 2.4 mmHg among subjects with a mean age of 22.8 years in this highly myopia Chinese population. These findings suggested that highly myopic Chinese persons of a younger age and greater central corneal thickness were more likely to have higher intraocular pressure.